Humpback Whales

Humpback Whales

Projecting the tracks of pods as they migrated past the northern tip of the Monte Bellos didn't quite lead directly to the Kimberley.

The Centre for Whale Research conducts research on Humpback whales in the following regions:

Dampier Archipelago

Monte Bello Islands

Kimberley

Exmouth/Ningaloo

Geraldton

Rottnest Island

Dampier Archipelago

We began our work in Western Australia in 1990 in the Dampier Archipelago. At the time we thought that its’ latitude, group of islands and water temperatures would create a similar calving area to those found in the northern hemisphere at Hawaii or the Bahamas, and, since no one could tell us where the Group IV calving area actually was, we decided to base our selves there for our first season. Operating from a tin shack on Enderby Island, loaned to us by the Department of Conservation and Land Management, we made daily forays out to what we now understand to be the southern migratory path past the islands. In those days, we called it the “Humpback Highway” because of the procession like progress of the whales as they headed almost directly west towards the top of the Monte Bellos Islands before heading south along the rest of the WA coast.

During the 5 years that we worked from the Dampier Archipelago, we photo-identified 987 whales, resighting, either between or within seasons, 233 of them. These 754 whales taught us a lot about what we didn’t know about Group IV humpback whales. For example, we sighted only 73 cow/calf pairs during this 5 year period so we realized very quickly that we still didn’t know where their calving grounds were.

We also realized that we didn’t understand the dynamics of the migratory paths of these whales on the WA coast. The northern migration was not visible to us within the range of our small inflatable nor apparently was a significant proportion of the southern migration. A population estimate we calculated (Jenner and Jenner, 1994, link to publications) based on sight/resight analysis was disappointingly biased due to the width of the southern migratory body, particularly at peak season, and our inability to photographically sample it effectively.

It was a very valuable start to our study, however, and the data gathered, together with the friends and associations we made in those early days, have proven to be the solid foundations of our now thriving research program.

Monte Bello Islands

The course of the pods more closely paralleled the off-shore bathymetry of the continental shelf.

In 1992, we were determined to test our hypothesis regarding the off-shore nature of the northbound migratory path across the Norwest Shelf area of Western Australia. The previous season we had begun our second season off Dampier (70nm to the east) in June, expecting to monitor the northern migration as humpback whales migrated past the Dampier Archipelago to an as yet undiscovered region in the Kimberley. We had spent two long months sighting only a handful of whales and only started really seeing whales in August, once the southern migration had begun, similar to the previous season. We could hear whales on our hydrophone throughout June and July, but we couldn’t actually see them, presumably because they were too far off-shore at Dampier. Our strategy was then to find a location that would allow us to intercept the northern migration on their way to the Kimberley and observe the course of the migration at that point. That point was the Monte Bello Islands.

With the logistical support of Dick and Andrew Morgan of Morgan Pearls, Bristow Helicopters and Woodside Petroleum, we spent four fascinating weeks photo-identifying and tracking humpback whales as they migrated north along the western side of the Monte Bellos’ reef and then turned northeast towards the Kimberley. During 4 weeks, we managed 14 field days, sighting 77whales in 37 pods. The average migratory heading of the 33 pods we followed past the northern reef edge was 46°true (+ 6°, 95%CI). However, projecting the whales path 600nm along this bearing didn’t quite land them directly in the Kimberley. Nothing is ever as easy as that! Instead, the bearings did closely resemble the 200 Ð 500m contour orientation in the immediate off-shore area – leading us to another hypothesis – that the whales migrated north by following the continental shelf break. This theory remained untested until 10 years later when we began analyzing a series of aerial surveys we conducted off North West Cape.(Link to Exmouth/Ningaloo)

Information about Humpback in the Kimberley, Exmouth/Nigaloo, Geraldton, and Rottnest Island coming soon….